* [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor
@ 2022-02-14 12:31 Nicholas Piggin
2022-02-14 13:16 ` Daniel Henrique Barboza
2022-02-14 13:32 ` Fabiano Rosas
0 siblings, 2 replies; 5+ messages in thread
From: Nicholas Piggin @ 2022-02-14 12:31 UTC (permalink / raw)
To: qemu-ppc; +Cc: qemu-devel, Nicholas Piggin
The spapr virtual hypervisor does not require the hdecr timer.
Remove it.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
hw/ppc/ppc.c | 2 +-
hw/ppc/spapr_cpu_core.c | 6 +++---
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
index 462c87dba8..a7c262db93 100644
--- a/hw/ppc/ppc.c
+++ b/hw/ppc/ppc.c
@@ -1072,7 +1072,7 @@ clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq)
}
/* Create new timer */
tb_env->decr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_decr_cb, cpu);
- if (env->has_hv_mode) {
+ if (env->has_hv_mode && !cpu->vhyp) {
tb_env->hdecr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_hdecr_cb,
cpu);
} else {
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index a781e97f8d..ed84713960 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -261,12 +261,12 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
return false;
}
- /* Set time-base frequency to 512 MHz */
- cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
-
cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
kvmppc_set_papr(cpu);
+ /* Set time-base frequency to 512 MHz. vhyp must be set first. */
+ cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
+
if (spapr_irq_cpu_intc_create(spapr, cpu, errp) < 0) {
qdev_unrealize(DEVICE(cpu));
return false;
--
2.23.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor
2022-02-14 12:31 [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor Nicholas Piggin
@ 2022-02-14 13:16 ` Daniel Henrique Barboza
2022-02-14 13:32 ` Fabiano Rosas
1 sibling, 0 replies; 5+ messages in thread
From: Daniel Henrique Barboza @ 2022-02-14 13:16 UTC (permalink / raw)
To: Nicholas Piggin, qemu-ppc; +Cc: qemu-devel
On 2/14/22 09:31, Nicholas Piggin wrote:
> The spapr virtual hypervisor does not require the hdecr timer.
> Remove it.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> hw/ppc/ppc.c | 2 +-
> hw/ppc/spapr_cpu_core.c | 6 +++---
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> index 462c87dba8..a7c262db93 100644
> --- a/hw/ppc/ppc.c
> +++ b/hw/ppc/ppc.c
> @@ -1072,7 +1072,7 @@ clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq)
> }
> /* Create new timer */
> tb_env->decr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_decr_cb, cpu);
> - if (env->has_hv_mode) {
> + if (env->has_hv_mode && !cpu->vhyp) {
> tb_env->hdecr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_hdecr_cb,
> cpu);
> } else {
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index a781e97f8d..ed84713960 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -261,12 +261,12 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
> return false;
> }
>
> - /* Set time-base frequency to 512 MHz */
> - cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
> -
> cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
> kvmppc_set_papr(cpu);
>
> + /* Set time-base frequency to 512 MHz. vhyp must be set first. */
> + cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
> +
> if (spapr_irq_cpu_intc_create(spapr, cpu, errp) < 0) {
> qdev_unrealize(DEVICE(cpu));
> return false;
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor
2022-02-14 12:31 [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor Nicholas Piggin
2022-02-14 13:16 ` Daniel Henrique Barboza
@ 2022-02-14 13:32 ` Fabiano Rosas
2022-02-14 18:05 ` Cédric Le Goater
1 sibling, 1 reply; 5+ messages in thread
From: Fabiano Rosas @ 2022-02-14 13:32 UTC (permalink / raw)
To: Nicholas Piggin, qemu-ppc; +Cc: qemu-devel, Nicholas Piggin
Nicholas Piggin <npiggin@gmail.com> writes:
> The spapr virtual hypervisor does not require the hdecr timer.
Why is that? Is this not needed for an emulated powernv running KVM
guests?
> Remove it.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> hw/ppc/ppc.c | 2 +-
> hw/ppc/spapr_cpu_core.c | 6 +++---
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> index 462c87dba8..a7c262db93 100644
> --- a/hw/ppc/ppc.c
> +++ b/hw/ppc/ppc.c
> @@ -1072,7 +1072,7 @@ clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq)
> }
> /* Create new timer */
> tb_env->decr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_decr_cb, cpu);
> - if (env->has_hv_mode) {
> + if (env->has_hv_mode && !cpu->vhyp) {
> tb_env->hdecr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_hdecr_cb,
> cpu);
> } else {
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index a781e97f8d..ed84713960 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -261,12 +261,12 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
> return false;
> }
>
> - /* Set time-base frequency to 512 MHz */
> - cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
> -
> cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
> kvmppc_set_papr(cpu);
>
> + /* Set time-base frequency to 512 MHz. vhyp must be set first. */
> + cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
> +
> if (spapr_irq_cpu_intc_create(spapr, cpu, errp) < 0) {
> qdev_unrealize(DEVICE(cpu));
> return false;
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor
2022-02-14 13:32 ` Fabiano Rosas
@ 2022-02-14 18:05 ` Cédric Le Goater
2022-02-14 22:59 ` Nicholas Piggin
0 siblings, 1 reply; 5+ messages in thread
From: Cédric Le Goater @ 2022-02-14 18:05 UTC (permalink / raw)
To: Fabiano Rosas, Nicholas Piggin, qemu-ppc; +Cc: qemu-devel
On 2/14/22 14:32, Fabiano Rosas wrote:
> Nicholas Piggin <npiggin@gmail.com> writes:
>
>> The spapr virtual hypervisor does not require the hdecr timer.
>
> Why is that? Is this not needed for an emulated powernv running KVM
> guests?
It is now also running in the QEMU pseries machine (L0) when a
nested is running. That's part of the implementation Nick did for
the KVM-on-pseries-in-QEMU-TCG.
But isn't that redundant with the cpu_ppc_hdecr_init() and
cpu_ppc_hdecr_exit() from the RFC ? and shouldn't that be
created only once, when the first nested is started or when
the machine is if cap-nested-hv=on ?
>> Remove it.
>>
>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>> ---
>> hw/ppc/ppc.c | 2 +-
>> hw/ppc/spapr_cpu_core.c | 6 +++---
>> 2 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
>> index 462c87dba8..a7c262db93 100644
>> --- a/hw/ppc/ppc.c
>> +++ b/hw/ppc/ppc.c
>> @@ -1072,7 +1072,7 @@ clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq)
>> }
>> /* Create new timer */
>> tb_env->decr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_decr_cb, cpu);
>> - if (env->has_hv_mode) {
>> + if (env->has_hv_mode && !cpu->vhyp) {
hmm, Can we have (env->has_hv_mode && cpu->vhyp) ? this is confusing :/
Thanks,
C.
>> tb_env->hdecr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_hdecr_cb,
>> cpu);
>> } else {
>> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
>> index a781e97f8d..ed84713960 100644
>> --- a/hw/ppc/spapr_cpu_core.c
>> +++ b/hw/ppc/spapr_cpu_core.c
>> @@ -261,12 +261,12 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
>> return false;
>> }
>>
>> - /* Set time-base frequency to 512 MHz */
>> - cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
>> -
>> cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
>> kvmppc_set_papr(cpu);
>>
>> + /* Set time-base frequency to 512 MHz. vhyp must be set first. */
>> + cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
>> +
>> if (spapr_irq_cpu_intc_create(spapr, cpu, errp) < 0) {
>> qdev_unrealize(DEVICE(cpu));
>> return false;
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor
2022-02-14 18:05 ` Cédric Le Goater
@ 2022-02-14 22:59 ` Nicholas Piggin
0 siblings, 0 replies; 5+ messages in thread
From: Nicholas Piggin @ 2022-02-14 22:59 UTC (permalink / raw)
To: Cédric Le Goater, Fabiano Rosas, qemu-ppc; +Cc: qemu-devel
Excerpts from Cédric Le Goater's message of February 15, 2022 4:05 am:
> On 2/14/22 14:32, Fabiano Rosas wrote:
>> Nicholas Piggin <npiggin@gmail.com> writes:
>>
>>> The spapr virtual hypervisor does not require the hdecr timer.
>>
>> Why is that? Is this not needed for an emulated powernv running KVM
>> guests?
Yeah, powernv does not use the virtual hypervisor, that's just for
pseries.
> It is now also running in the QEMU pseries machine (L0) when a
> nested is running. That's part of the implementation Nick did for
> the KVM-on-pseries-in-QEMU-TCG.
>
> But isn't that redundant with the cpu_ppc_hdecr_init() and
> cpu_ppc_hdecr_exit() from the RFC ? and shouldn't that be
> created only once, when the first nested is started or when
> the machine is if cap-nested-hv=on ?
For now I create the timer for a vcpu while it is in H_ENTER_NESTED
and destroy it when the hcall returns.
Thanks,
Nick
>
>>> Remove it.
>>>
>>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>>> ---
>>> hw/ppc/ppc.c | 2 +-
>>> hw/ppc/spapr_cpu_core.c | 6 +++---
>>> 2 files changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
>>> index 462c87dba8..a7c262db93 100644
>>> --- a/hw/ppc/ppc.c
>>> +++ b/hw/ppc/ppc.c
>>> @@ -1072,7 +1072,7 @@ clk_setup_cb cpu_ppc_tb_init (CPUPPCState *env, uint32_t freq)
>>> }
>>> /* Create new timer */
>>> tb_env->decr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_decr_cb, cpu);
>>> - if (env->has_hv_mode) {
>>> + if (env->has_hv_mode && !cpu->vhyp) {
>
> hmm, Can we have (env->has_hv_mode && cpu->vhyp) ? this is confusing :/
>
> Thanks,
>
> C.
>
>
>>> tb_env->hdecr_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &cpu_ppc_hdecr_cb,
>>> cpu);
>>> } else {
>>> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
>>> index a781e97f8d..ed84713960 100644
>>> --- a/hw/ppc/spapr_cpu_core.c
>>> +++ b/hw/ppc/spapr_cpu_core.c
>>> @@ -261,12 +261,12 @@ static bool spapr_realize_vcpu(PowerPCCPU *cpu, SpaprMachineState *spapr,
>>> return false;
>>> }
>>>
>>> - /* Set time-base frequency to 512 MHz */
>>> - cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
>>> -
>>> cpu_ppc_set_vhyp(cpu, PPC_VIRTUAL_HYPERVISOR(spapr));
>>> kvmppc_set_papr(cpu);
>>>
>>> + /* Set time-base frequency to 512 MHz. vhyp must be set first. */
>>> + cpu_ppc_tb_init(env, SPAPR_TIMEBASE_FREQ);
>>> +
>>> if (spapr_irq_cpu_intc_create(spapr, cpu, errp) < 0) {
>>> qdev_unrealize(DEVICE(cpu));
>>> return false;
>>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-02-14 12:31 [PATCH] spapr: prevent hdec timer being set up under virtual hypervisor Nicholas Piggin
2022-02-14 13:16 ` Daniel Henrique Barboza
2022-02-14 13:32 ` Fabiano Rosas
2022-02-14 18:05 ` Cédric Le Goater
2022-02-14 22:59 ` Nicholas Piggin
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